JP2001120913A - Stitching structure of slurry feed hole of filter cloth for center field type filter press - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve stitching structure of slurry feed holes of filter cloth for a center field type filter press in which a pair of two sheets of the filter cloths covering both front and rear surfaces of a filter plate where slurry feed holes are provided by boring and a united cloth hyperboloid sheet body covering the slurry feed holes are united by machine stitching. SOLUTION: Uniting machine stitching is applied to superposing parts between the united cloth and the pair of two sheets of filter cloths covering both front and rear surfaces of the filter plate. X denotes an end edge of the superposing part between the united cloth and the filter cloths at a side near the center of the slurry feed holes. Y denotes an end edge of the superposing part between the united cloth and the filter cloths at a side remote from the center of the slurry feed holes. Two or three lines of machine stitching are arranged at positions between 2 mm and 5 mm from the end edge X and/or the end edge Y in approximately parallel to curves of peripheral edges at 1 to 2 mm intervals. Then, machine stitching of zigzag shape is applied to the superposing part between the filter cloths and the united cloth at 7 to 15 mm intervals in a normal direction from the center of the slurry feed holes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hyperboloid sheet body (hereinafter referred to as a "combined body") in which a pair of filter cloths covering both front and back surfaces of a filter plate provided with a slurry supply hole covers the slurry supply hole. Sewing machine in a center feed type filter press filter cloth for slurry feed hole, which is combined with sewing machine sewing, avoids damage to sewing machine parts due to sewing machine thread change while sewing machine thread remains unchanged. The present invention relates to a sewing structure of a slurry supply hole of a filter cloth for a center feed type filter press which contributes to an improvement in process efficiency.

[0002]

BACKGROUND OF THE INVENTION Filtration operations have improved with the development of various industries, such as the chemical, mining and food industries. Improved operation of the filter press,
Development is no exception.

[0003] The development of a single-type filter press in which a filter chamber is formed by two opposing filter cloths and a cake is formed between the two filter cloths has been developed in order to reduce the filtration area within the limited installation area of the filter. Dramatically increased, contributing to more efficient filtration work. Above all, the idea and development of a center-feed type filter press (hereinafter, referred to as "filter press") in which a slurry supply hole is formed in an effective filtration surface of a filter plate was epoch-making.

[0004] Initially, the filter cloth was fixed to the liquid supply hole with a grommet of a threaded communication pipe. However, the filter cloth was twisted or wrinkled with the rotation of the screw, and it was very difficult to mount the filter cloth accurately. It was difficult. In the 1960's, Japanese Utility Model Publication No. 41-18220 or Japanese Utility Model Publication No. 41-18222 were devised, and difficulties in grommet operation were avoided, and the benefits are still enjoyed today.

The invention of Japanese Utility Model Publication No. 41-18220 to Japanese Utility Model Publication No. 41-18222 is as shown in FIG. 1A, 1B, and 1C, the slurry supply hole 2
A pair of filter cloths 4, 4 covering the front and back surfaces 3, 3 of the filter plate 1 pierced with the filter plate 1 are interposed via a hyperboloid sheet body 5 (hereinafter referred to as “bonding cloth”) covering the slurry supply holes 2. In various ways. The basics of the connection form are shown in FIG. As described above, the pair of filter cloths 4 and 4 are bonded via the bonding cloth 5, and the bonding cloth 5 is in the vicinity of a portion that comes into contact with the slurry supply hole 2 formed in the filter plate 1. The joining cloth 5 is joined while being contracted so as to be pushed in, and the joining cloth 5 is joined by operating the extension cloth 5 in the vicinity of the outer peripheral green 7 so as to be pulled.

As shown in FIG. 2, the joining cloth 5 is attached to the contact surfaces 6, 6 of the joining cloth 5 and the filter cloths 4, 4.
And a method in which both are simultaneously pressed (T) (T) while blowing hot air at a temperature higher than the melting point of the filter cloth 4.

The contact surfaces 6, 6 between the binding cloth 5 and the filter cloths 4, 4
A “hot melt adhesive sheet” (not shown) having a melting point lower than the melting points of the bonding cloth 5 and the filtering cloth 4 is disposed on at least one side of both the bonding cloth 5 and the filtering cloth 4. A method of pressing both at once while blowing hot air at a temperature higher than the melting point of the sheet.

The contact surfaces 6, 6 between the binding cloth 5 and the filter cloths 4, 4
A method of simultaneously contacting a "trowel" (not shown) heated to a temperature higher than the melting points of the bonding cloth 5 and the filter cloth 4, and immediately pressing both at once.

Contact surfaces 6, 6 between the binding cloth 5 and the filter cloths 4, 4
Then, an adhesive is applied to both opposing surfaces or one surface by means of application or the like, and both are pressed together at once.

A method in which both the joining cloth 5 and the filter cloths 4 and 4 are joined by sewing (not shown). Can be considered.

[0011] The most reliable method is to bond both the bonding cloth 5 and the filter cloths 4 and 4 by sewing. Has been adopted.

FIG. 3A shows an example of the "method of joining both the joining cloth 5 and the filtering cloths 4 and 4 by sewing."
To (D).

FIG. 3A shows a case in which a pair of filter cloths 4 and 4 are slightly separated from each other by a distance L, and the sewing machine 8 is sewn through a connecting cloth 5 to be connected. This is adopted when 4 is rigid. Alternatively, this method may be employed even when the filter plate 1 is thick.

FIG. 3B shows a case in which a pair of filter cloths 4 and 4 are separated by a predetermined distance M, and are sewn together by a sewing machine 8 via a connecting cloth 5. This is adopted when the filter plate is thickened by arranging a compression membrane.

FIG. 3 (C) shows the most general form, in which a pair of two filter cloths 4 and 4 are stitched together at the center side of the slurry supply hole 2 with a sewing machine 9 (in the industry, this is referred to as "worship sewing"). This is the case where the joining cloth 5 is arranged after the joining, and the sewing sewing 8 is applied to join. According to this method, it is possible to prevent particles in the slurry from entering from the joint portion 9 'of the pair of filter cloths 4 and 4.

The forms shown in FIGS. 3 (A) to 3 (C) generally have a structure in which the binding cloth 5 is woven into a thick single or double weave mainly using spun yarn, and is thick and flexible. As a result, the thread of the sewing machine 8 serves to prevent the thread of the sewing machine 8 from directly coming into contact with the filter plate or the compressed membrane, and is used conveniently. There is little fear that the filter cake remains in the portion.

However, although the reason cannot be clearly pointed out, the bonding cloth 5 may be arranged on the filter cake attaching side 10 as shown in FIG. 3D due to special circumstances.

FIGS. 4A and 4B show a filter cloth 4 and a binding cloth 5.
And the state of the sewing machine 8 shown in FIG. FIG. 4B is a cross-sectional view. Generally, a plurality of sewing stitches 8 are concentrically applied to the entire surface of the outer edge 12 of the coupling cloth 5 from the edge 11 on the center side of the liquid supply hole of the filter cloth 4.

As in recent years, the operating conditions of the chemical industry equipment have become strict, and the demand for higher precision of solid-liquid separation (reduction of the residual liquid in the filter cake) has increased. The high-pressure squeezing of the filter cloth has been carried out, and a high-strength bond between the filter cloth 4 and the bonding cloth 5 has been required.

As one of the countermeasures, there is a method of increasing the number of sewing stitches 8 to increase the bonding strength, as shown in FIGS. 5 (A) and 5 (B). This is very easily conceived and routinely performed by those skilled in the art, but its effectiveness is not necessarily denied.

However, if the number of sewing stitches 8 is increased, the portion may be hardened, and it may be difficult to mount the filter cloth on the filter. Then, when the sewing thread is sewn, the filter cloth 4 and the binding cloth 5 when the sewing needle moves up and down at a high speed are displayed.
In some cases, the filter cloth 4 and the bonding cloth 5 are also weakened by friction or heat, and the desired strength may not be obtained.

As a next countermeasure, it is extremely easy to conceive that the sewing thread 8 shown in FIGS. 5A and 5B is made of a high-strength material, and is routinely executed. The effectiveness of this is also not denied.

As a sewing thread having sufficient heat resistance and high strength,
"Technola", an aramid fiber yarn manufactured by Teijin Limited, or "Kepler", an aramid fiber yarn developed by Du Pont of the United States, is famous and actually used. The thickness of the sewing thread is in the range of about 400 to 2000T in international unit system,
It is appropriately selected according to hardness and strength. Of course, if one has ordinary knowledge in the art, a thread outside the above range can be selected according to the situation, and is routinely applied.

However, these aramid fiber yarns exhibit very high tenacity, but have only a "high Young's modulus" and therefore have low extensibility to stress and "high hardness". Often, abrasion occurs as a groove having a width corresponding to the thickness of the sewing thread is formed in a portion (thread path) that contacts the thread. For this reason, the sewing machine thread made of aramid fiber thread may not have the strength in actual use as expected. In order to avoid this, it is necessary to replace and maintain the parts of the "thread path" at regular intervals, which is inefficient and extremely uneconomical.

[0025]

According to the present invention, there is provided a combined body (hyperboloid sheet body) comprising a pair of filter cloths covering the front and back surfaces of a filter plate having a slurry supply hole, the cover plate covering the slurry supply hole. In the sewing structure of the slurry supply hole of the filter cloth for the center feed type filter press joined by sewing,
The sewing machine stitched on the overlapped portion of the pair of filter cloths covering the front and back surfaces of the filter body with the pair of filter cloths is formed by polymerizing the combination body and the filter cloth on the side near the center of the slurry supply hole. An edge (X) and / or an edge (Y) of an overlap portion (Y) between the filter cloth and an edge (X) of the portion and a portion farther from the center of the slurry supply hole; From the time 2
After arranging two or three sewing stitches at an interval of 1 to 2 mm substantially in parallel with the curve of the peripheral edge at a position between 5 mm to 5 mm, the overlapping portion of the filter cloth and the combined body is disposed from the center of the slurry supply hole. A zigzag sewing machine is provided at intervals of 7 to 15 mm in the normal direction (claim 1).

According to the present invention, the zigzag sewing machine is provided over the entire periphery of the slurry supply hole (claim 2), or the zigzag sewing machine sewing is performed on a specific selected portion of the slurry supply hole. It is desirable that it be applied (claim 3). In addition, the sewing machine stitches substantially concentrically with an appropriate interval between two or three sewing stitches applied to a portion between 2 and 5 mm from the edge (X) and the edge (Y). Is preferably added before or after the zigzag sewing.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention have shown in FIG. 5 (a) a filter cloth for a filter press in which the operating conditions of the chemical industry equipment have become severer and the high-pressure injection of slurry and high-pressure compression of the filter cake have been performed. A) The filter cloth 4 shown in (B)
And the state of bond breaking of the bonding cloth 5 was observed. FIG. 5 (A)
In (B), the innermost edge [hereinafter referred to as “edge (X)” ”of the central portion of the slurry supply hole at the seam of the filter cloth 4 and the binding cloth 5 may be used. Sewing thread 81 or filter cloth 4]
And the outermost edge [hereinafter referred to as “edge (Y)” ”at the stitched portion of the joining cloth 5. ] Was broken first, and the next sewing thread was observed to break sequentially.

FIGS. 6A and 6B are conceptual diagrams of a sample 50 for measuring the sewing strength of the filter cloths 4 and 4 and the binding cloth 5 using the sewing thread 8. The sample 50 was set on a tensile strength measuring device (not shown), and
The tensile strength at the time of pulling was measured. The sample width is 5 cm.

FIG. 6 (C) shows a sample 5 sewn as shown in FIGS. 6 (A) and 6 (B) with a polypropylene fiber sewing thread # 5 (international unit: a stranded thread having a thickness equivalent to 1330 T).
The results of a suture strength measurement example of 0 are shown. As the number of sutures increases, the suture strength increases. The specifications of the filter cloth 4 and the binding cloth 5 in this sample are as shown in the following [Table 1]. The pitch of the perforations is 5 mm.

[0030]

[Table 1]

The constituent yarns are all twisted yarns.

In the measurement of the suturing strength according to FIG. 6C, the tendency of the filter cloth 4 shown in FIGS. 6A and 6B to be sequentially broken from the sewing thread 81 near the edge of the filter cloth 4 was also observed. Was.
It is considered that this tendency has remarkably appeared in actual use sites. The graph of FIG. 6C is obtained by deleting the data when the sewing thread is sequentially broken from near the edge and connecting the numerical values plotted.

Incidentally, the binding cloth has a texture: 1/7 twill weave double weave,
Constituent yarn: For both warp and weft: PP multi 10 PP spun mixed twisted yarn 8th equivalent thickness Multiplied by 190T equivalent thickness multi, density: 72 warps / 2.54 cm x 40 wefts / 2.54 cm
Is preferably applied.

According to the material of the filter cloth 4, if the filter cloth 4 is polyester (PET), the bond cloth 5 is also polyester (PET). If the filter cloth 4 is polyamide (PA), the bond cloth 5 is also polyamide (PA). It is a matter of course that PA) is replaced with the above specification and used.

A material which exceeds the heat resistance, chemical resistance, abrasion resistance and high strength of the filter cloth 4, such as the aramid fiber yarn, the fiber made of polytetrafluoroethylene (PTFE), the fiber made of polyphenylene sulfide (PPS) or Known high-performance fibers such as polyetheretherketone (PEEK) fibers and polyvinylidene fluoride fibers may be used alone or mixed with each other, or may be mixed with the PET fibers, PP fibers or PA fibers to improve durability. It is routinely practiced in the industry.

In actual use, as described above, FIG.
In (A) and (B), the sewing thread 81 of the innermost edge 11 of the center portion of the slurry supply hole or the sewing portion of the filter cloth 4 and the binding cloth 5 at the stitched part of the filtering cloth 4 and the binding cloth 5 is used. Outermost edge 1
It was observed that the second sewing thread 82 was broken first, and the next sewing thread was broken sequentially.

Then, as shown in FIGS. 7 (A) and 7 (B), the present inventor prepared a sample 60 for measuring the suture strength with the sewing thread 8 of the filter cloths 4, 4 and the binding cloth 5, and prepared the same sample 60. Installed on a tensile strength measuring device (not shown),
The breaking strength when the sample 60 was pulled in the direction 1 was measured. At the sewn portion of the filter cloth 4 and the binding cloth 5, two sewing stitches 62 at the innermost edge 11 at the center side of the slurry supply hole are 1 mm in length.
, Or two sewing stitches 63 on the outermost peripheral edge 12 at the seam of the filter cloth 4 and the binding cloth 5 are arranged at an interval of 1 mm. Then, a sewing stitch 64 is applied between the sewing stitches 62 and 63 to fix the relative positions of the filter cloth 4 and the binding cloth 5, and as shown in FIG. 7A, the zigzag sewing stitch 65 is reduced to the entire width of the sample of 5 cm. It was applied almost evenly throughout. Zigzag sewing stitch 65 spacing 66
Was 7 mm.

Sample number n = 5, minimum strength: 652 daN
/ 5 cm, maximum strength 764 daN / 5 cm, average 712
daN / 5 cm. This is because the number of sewing threads in the example of measuring the sewing strength of the sample 50 sewn as shown in FIGS. 6A and 6B with a sewing thread # 5 made of polypropylene fiber (international unit: a stranded yarn equivalent to 1330 T) as shown in FIGS. This is equivalent to the suture strength of a book. In the measurement of the suturing force, the entire sewing thread was broken at once without observing the tendency of the sewing thread 62 to be sequentially broken from the sewing thread 62 near the edge 11 of the filter cloth 4 in FIGS. 7 (A) and 7 (B). It was expected that this situation would be maintained even in the actual use site, and that the suture strength be maintained for a long period of time under severe filtering operation.

[0039]

EXAMPLE In accordance with the results of the measurement of the suture strength of the samples shown in FIGS. 7A and 7B, as shown in FIGS. 8A and 8B, the sewing with the sewing thread 8 of the filter cloth 4 and the binding cloth 5 was performed. .

[Table 2] summarizes the elements of the sewing specifications of the filter cloth in a table.

[0041]

[Table 2]

The gap between the innermost edge 11 of the central part of the slurry supply hole and the sewing machine stitch 62 in the stitching portion is 2 to 5 mm, and the two sewing machine stitches are arranged at an interval of 1 to 2 mm. It is preferable that the gap between the outermost peripheral edge 12 and the sewing machine stitch 63 at the seam portion of the joining cloth 5 is 2 to 5 mm, and the two sewing machines are arranged side by side at a distance of 1 to 2 mm. Here, the number is two, but the number may be selected in a range of two or three according to the situation. The length of the sewing seam is
It is better to set it between 3 and 5 mm. The zigzag sewing interval is preferably selected in the range of 7 to 15 mm.

Outside of this selection range, the formation of the suture is impractical.

When a filter cloth having the above specifications is used for a filter press in a manufacturing process of various kinds of precipitated calcium carbonate for industrial use, as shown in FIG. 5 (B), the number of sewing machines 8 is increased to increase the bonding strength. While the product tried to be broken after about one week of use, it could withstand long-term use until the performance of the filter cloth was impaired by continuous use for about 120 days. this is,
8 (A) and 8 (B), the sewn portions of the filter cloths 4 and 4 and the binding cloth 5 with the sewing thread 8 are used to sew the filter cloth 4 and the binding cloth 5 at the center of the slurry supply hole. Innermost edge 1
This is because two sewing stitches 62 are arranged at intervals of 1 mm, and two sewing stitches 63 of the outermost peripheral edge 12 are arranged at intervals of 1 mm at the seam of the filter cloth 4 and the joining cloth 5. This is judged to be the effect of the seam strengthening and the strength of the seam extending in the radial direction from the center of the liquid supply hole by the zigzag sewing machine stitch 65 uniformly applied to the entire surface of the joining cloth.

The zigzag sewing machine 65 extending in the radial direction from the center of the liquid supply hole evenly applied acts so that the sewing thread 65 'grasps the filter cloth 4 and the coupling cloth 5 while sewing them as shown in FIG. The filter cloth 4 and the binding cloth 5 in the radial direction.
It is judged that the effect of increasing the strength of the suture was enhanced by giving a “room for expansion and contraction” to buffer the sudden expansion of the compressed membrane.

The filtration conditions in this step were as shown in Table 3 below. [Table 3] Nominal specifications of filter: Center feed automatic filter press 1500 × 35 rooms

[0047]

[Table 3]

In the conceptual views of FIGS. 8A and 8B, when the filter cloths 4 and 4 and the binding cloth 5 are sewn with the sewing thread 8, the slurry is The sewing thread 62 and / or the sewn portion of the filter cloth 4 and the binding cloth 5 arranged at an interval of 1 mm at the innermost edge 11 of the center side portion of the supply hole and an interval of 2 mm at the outermost peripheral edge 12 at the seam portion The sewing machine thread 63 arranged with the fibers is made of a material that exceeds the heat resistance, chemical resistance, abrasion resistance and high strength of the filter cloth 4, such as the aramid fiber thread or polytetrafluoroethylene (PTFE). Fiber, polyphenylene sulfide (P
PS) fiber or polyetheretherketone (PE
Known high-performance fibers such as EK) fibers and polyvinylidene fluoride fibers may be used alone or mixed with each other, or may be mixed with the PET fibers, PP fibers or PA fibers so as not to damage mechanical parts of the sewing machine (for example, It is also possible to use a sewing thread having a two-layer structure in which functional fibers are used as a core component and ordinary fibers such as PET fibers and PP fibers are used as a sheath component.

Further, the zigzag sewing machine is included in the sewing structure of the present invention even if it is selectively applied within a range surrounding the damaged portion in accordance with the use state and the broken state of the filter cloth.

[0050]

8 (A) and 8 (B) of the above embodiment, the sewn portions of the filter cloth 4 and the connecting cloth 5 by sewing the filter cloths 4 and 4 and the connecting cloth 5 with the sewing thread 8. 2 stitches of the sewing machine 62 at the innermost edge 11 at the center side of the slurry supply hole.
m, and two sewing stitches 65 on the outermost peripheral edge 12 are laid side by side at an interval of 1 mm at the sewn portion of the filter cloth 4 and the bonding cloth 5 to strengthen the sewn edges and bond cloth. Zigzag sewing machine stitches 65, which are uniformly applied to the entire surface of the sewing machine, extend radially from the center of the liquid supply hole.
5 'acts so as to grasp the filter cloth 4 and the binding cloth 5 while sewing the filter cloth 4 and the binding cloth 5, so that the filter cloth 4 and the binding cloth 5 are given a "expansion / expansion margin" in the radial direction to buffer the sudden expansion of the compressed film. As a result, the effect of improving the suture strength is enhanced, the filter can withstand severe filtering operations for a long period of time, and the operation of the filtering process can be stably continued.

[Brief description of the drawings]

1 (A), 1 (B) and 1 (C) show the basics of a filter plate in which both front and back surfaces of a filter plate and a slurry supply hole are stretched so as to be covered with a pair of filter cloths and a bonding cloth for connecting the filter cloths. In the drawings showing the structure, (A) is a front view of a filter plate in which a part of the filter cloth is cut,
(B) is a cross-sectional view of the filter plate cut at the center of the slurry supply hole, and (C) is a perspective view showing the relationship between the filter plate, the filter cloth, and the binding cloth around the slurry supply hole.

FIG. 2 is a perspective view showing a relationship between a pair of two filter cloths and a binding cloth.

3 (A), 3 (B), 3 (C), and 3 (D) are cross-sectional views showing different examples of a state in which a pair of two filter cloths are connected to each other by sewing means using a connecting cloth.

4 (A) and 4 (B) are a front view and a cross-sectional view of a state in which a pair of filter cloths are connected by a sewing means shown in FIG.

5 (A) and 5 (B) are a front view and a cross-sectional view of an improved example which is connected by the sewing means of FIG. 4;

6 (A) and 6 (B) are conceptual diagrams of a sample for cooperative sewing measurement using a sewing thread of a filter cloth and a bonding cloth, which are joined by the sewing means of FIG. 5, (A) is a plan view, and (B) Is a cross-sectional view, and (C) is a characteristic diagram showing the results of the suture strength measurement of the samples of (A) and (B).

7 (A) and 7 (B) are conceptual diagrams of a sample for cooperative measurement of sewing of a filter cloth and a binding cloth with a sewing thread according to the present invention.

8 (A) and 8 (B) are a plan view and a cross-sectional view of a sewing machine using the sewing thread according to the present invention.

FIG. 9 is a view showing a zigzag sewing state of a filter cloth and a binding cloth with upper and lower sewing threads.

[Explanation of symbols]

1. Filter plate 2. Slurry supply hole 3. 3. Front and back of filter plate Filter cloth 5. 7. Bonding cloth (hyperboloid sheet body) Sewing thread 11. 11. Innermost edge of central part of slurry supply hole Outermost edge at the seam of filter cloth and binding cloth 62.63.64. Sewing thread 65. Zigzag sewing

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[Procedure amendment]

[Submission date] November 10, 1999 (1999.11.
10)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

The invention of Japanese Utility Model Publication No. 41-18220 and Japanese Utility Model Publication No. 41-18222 is as shown in FIG. 1A, 1B, and 1C, the slurry supply hole 2
A pair of filter cloths 4, 4 covering the front and back surfaces 3, 3 of the filter plate 1 pierced with the filter plate 1 are interposed via a hyperboloid sheet body 5 (hereinafter referred to as “bonding cloth”) covering the slurry supply holes 2. In various ways. Details of the connection form are shown in FIG. As described above, the pair of filter cloths 4 and 4 are bonded via the bonding cloth 5, and the bonding cloth 5 is in the vicinity of the portion that comes into contact with the slurry supply hole 2 formed in the filter plate 1. The joining cloth 5 is joined while being contracted so as to be pushed in, and the joining cloth 5 is joined near the outer peripheral edge 7 of the joining cloth 5 by being slightly extended so as to be pulled.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Fig. 6

[Correction method] Change

[Correction contents]

6 (A) and 6 (B) are conceptual diagrams of a sample for measuring suture strength using a sewing thread of a filter cloth and a binding cloth, which are joined by the sewing means of FIG. 5, (A) is a plan view, and (B) 3 is a cross-sectional view, and (C) is a characteristic diagram showing the results of the measurement of suture strength of the samples (A) and (B).

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] Fig. 7

[Correction method] Change

[Correction contents]

FIGS. 7A and 7B are conceptual diagrams of a sample for measuring a suture strength of a filter cloth and a binding cloth according to the present invention using a sewing thread.

Claims (4)

[Claims] 1. A filter cloth for a center-feed filter press, wherein a pair of filter cloths covering both the front and back surfaces of a filter plate provided with a slurry supply hole are combined with a combined body covering the slurry supply hole by sewing. In the sewing structure of the slurry supply hole, the combined sewing machine stitched on the overlapping portion of the combined body and the pair of two filter cloths covering the front and back surfaces of the filter plate is provided on the side close to the center of the slurry supply hole. The edge (X) of the overlap (X) of the overlap portion of the combined body and the filter cloth and the edge (Y) of the overlap portion of the combined body and the filter cloth farther from the center of the slurry supply hole. And / or two or three sewing stitches are arranged at a position between 2 and 5 mm from the edge (Y) at an interval of 1 to 2 mm substantially parallel to the curve of the peripheral edge, and then the filter cloth and the Direction from the center of the slurry supply hole to the polymerization part of the combined body in the normal direction Sewing structure of center feed type filter press filter cloth for a slurry supply hole, characterized in that at intervals of 7~15mm subjected to zigzag sewing machine. 2. A sewing structure of a slurry supply hole of a filter cloth for a center feed type filter press according to claim 1, wherein a zigzag sewing machine is provided over the entire periphery of the slurry supply hole. . 3. A sewing structure for a slurry supply hole of a filter cloth for a center feed type filter press according to claim 1, wherein a zigzag sewing machine is provided on a specific selected portion of the slurry supply hole. 4. A method according to claim 1, wherein the edge is formed at a position between 2 and 5 mm from the edge (X) and the edge (Y).
The sewing machine according to any one of claims 1 to 3, wherein sewing machines are substantially concentrically added before or after the zigzag sewing machine at appropriate intervals between the book sewing machines. Sewing structure of slurry supply hole of filter cloth for feed type filter press.